I don’t see many roadies using hydration packs but once you hit the trails they are everywhere. I use a Nathan HPL 008 when I go out on my long unsupported trail runs. I can’t stand to have anything around my waist either.

On the rare occassions when I do go on a long run on the road I don't use the Nathan. I know where all the water fountains are so I don't bother. But the trail, you better believe I'm taking the pack with me.

I use one for my long runs and in half marathons. Makes me more comfortable to have it because I can drink at will and on long runs I have fewer excuses to turn back I don't see a lot of other people with them, but that doesn't bother me. Just make sure you have it adjusted properly to start and adjust again as you drink because on really long runs chafing can be a problem.

I wear a light Nathan Minimist hydration pack when I run. I sweat a lot and it gets really hot here in Texas during the summer. I tried the belts and they drove me batty and just can't stand them. I got used to the packs while mountain biking so they are pretty comfortable. It holds my GUs and phone which is an extra bonus.

I don't see many runners with them at all. So is there something wrong with wearing one, especially for long runs?

I live in Southern CA and it gets warm here sometimes (80º+). I have a water bottle belt (4 bottles of 8 OZ) and a backpack (64 OZ I think). They're both from Nathan and they're very well designed and manufactured.

The belt helps me for runs of 6 to 12 miles but, when it gets warm, I toss on the backpack and it works out well.

I've worn the belt during half marathons. The belt itself is just a few ounces and but the water, of course, costs me timewise (1 pound = 2 seconds per mile) but it allows me to skip water stops and it allows me to drink at my own pace.

I use the camelbak marathoner for my long runs and love it. I'm a big guy and it stays put. Never had any problems with it.